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Why?
On 27 Mar, 12:22, "Wimpie" wrote:
On 27 mar, 19:47, "art" wrote: On 27 Mar, 10:20, (Richard Harrison) wrote: Jim Pennino wrote: "Have you ever heard of a helix?" Most would likely enjoy Kraus` story of his invention of the axial-mode helix in his 3rd edition of "Antennas". This is a choice book! Best regards, Richard Harrison, KB5WZI I have his second edition and I find no mention of radiation from the beginning where current is applied onwards. Have you found anything that can contribute other than empirical grounds? You have avoided the question so far Hello Art, Radiation from accelerating charge is fully understood (from theory and verified practically), hence antenna theory. When you take the complete formula for fields (near and far) generated by a short wire segment (hertzian dipole), you can calculate the far and near field (magnitude, orientation, phase, etc) from every construction. The only problem is that you have to know the current distribution in your construction. It is not of interest whether the charge is excited by just a voltage source or EM radiation (like in reflection of waves on conductors and dielectrics). This is done in many FEM programs. Of course in many practical circumstances it is easier to use the "laws" from other people (that are derived from basic theory). One of the results are the Fresnel formulas for reflection. When you know the properties of the soil at the operating frequency, you can calculate the complex surface impedance and hence the complex reflection coefficient. Just mentioning words as "curl", "vector", "Gaussian" etc, doesn't make sense without further information. Best Regards, Wim- Hide quoted text - - Show quoted text - Wim Earlier I explained that the gaussian law can be expanded to provide a link to a radiator. The mathematics has been provenon this newsgroup. Unfortunately only one person accepted that proof. Using this new aproach,thesis or what have you provided for the generation of arrays where all radiator were resonant which provides specific advantages. It also provides for multiple arrangements of elements for maximum gain by virtue of the condition that equilibrium must be maintained in the enclosed volume of a standard Gaussian field which means that more than one arrangement of a given number of radiating elements can be arrived at for maximum gain. Thus not only was the theory proved by mathematics in accordance with known laws it has also been overchecked by the use of the equilibrium condition which was imposed as well as all being confirmed by accepted computor programs. Since all new theorem are immediately rejected by the vast majority of this group but with one exception from down under you surely can understand the futility of convincing people until they see it written in a book because of their lack of individual thought. One thing I have proved to my satisfaction that many who perceived themselves as experts have shown quite clearly that they have over estimated their abilities. When my work is published it will not only be seen that many were unable to think on the basis of there own knoweledge but also their knowledge of Electrical laws were flawed. That was my intention to prove when I introduced extension of known laws on this newsgroup plus the exposure to all of the residing pseudo experts. Time will tell that I have suceeded in my mission Regards Art |
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Art wrote:
"Earlier I explained that Gaussian law can be expanded to provide a link to a radiator." I am one who missed Art`s explanation. I am curious as Gauss and antennas have not been directly related in my mind. Wikipedia says: "The total of electric flux out of a closed surface is equal to the charge divided by the permittivity." J.C. Maxwell may have found Gauss useful, but why do I need him in amateur antenna wotk? Best regards, Richard Harrison, KB5WZI |
Why?
On 2 Apr, 09:43, (Richard Harrison) wrote:
Art wrote: "Earlier I explained that Gaussian law can be expanded to provide a link to a radiator." I am one who missed Art`s explanation. I am curious as Gauss and antennas have not been directly related in my mind. Wikipedia says: "The total of electric flux out of a closed surface is equal to the charge divided by the permittivity." J.C. Maxwell may have found Gauss useful, but why do I need him in amateur antenna wotk? Best regards, Richard Harrison, KB5WZI If you add time to both sides of the Gaussian law you have the connection which is more specific than that stated in Maxwell laws .Specific means the shape of the radiating cluster in question upto and including resulting radiation desirables. A quick search on "Gaussian" will bring you upto date All have been extensively stated. Art Art |
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Richard Harrison wrote:
[snip] Terman says on page 883: "For purposes of calculation, it is convenient to consider Richard, Great quote! If people listened to the words of the master, there would be far fewer arguments on RRAA. 73, Gene W4SZ |
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On 26 Mar, 19:27, "Jimmie D" wrote:
"art" wrote in message ups.com... Antennas seemed to have evolved into structures that are parallel or at right angles to the earths surface Why is this or is it asthetics that is driving this thinking? My research on the subject evolves around the vector formation of radiation and where the addition of the vectors involved which creats radiation is at an angle to the radiator.. This suggests that for best radiative advantage it is this vector that should be parallel to the earths surface and not the physical radiator. This appears to be born out by following my Gaussian approach to radiator design. So the question of habitual arrangement of antenna arrays parallel or at right angles to the earths surface as being the best arrangement needs some sort of validation. Any thoughts as to why it should be so and the scientific facts that support it? Art What angle did you derive was the best angle to mount an anenna? Please show experimental data to backup your conclusions. Jimmie- Hide quoted text - - Show quoted text - I searched thru Google and I see there is a lot of work going on with respect to tilting in the GHz area. Apparently some antennas come equiped with remote mechanical as well as digital type switchers. I found one commercial vertical antenna that was FIXED at a 3 degree tilt which is about what I found with a high frequency version for max vertical gain. Seems like the majority are going for mechanical tilting as digital delay style tilting is having an adverse action on the beam itself. I cannot find any literature that supplies technical backup so I suspect they are the result of emperical work and not mathematically as I have.It does seem that many are using tilt angle for accuracy in TOA for various reasons. By the way I have found that with cluster form this tilt angle is progressive with respect to close spaced elements in both horizontal and vertical forms. Seems like the commercials are spending a lot of money with repect to tipping for WiFI which requires extreme accurracy between nodes and where inaccurracy becomes progressive in deteriation. All very fascinating at least for non amateurs. Art |
Why?
On 4 Apr 2007 16:38:23 -0700, "art" wrote:
All very fascinating at least for non amateurs. We've been doing it for years on repeaters. It's called "down tilt" eBay has kits for sale as does: www.hotflashesatthetower.com (Andrew Antenna Down Tilt Mounting Kit 602030A. US $9.99) Proving anything can be patented, that was done 10 years ago: 5798675 Continuously variable phase-shifter for electrically down-tilting an antenna and on and on and on.... 73's Richard Clark, KB7QHC |
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On 26 Mar, 21:49, (Richard Harrison) wrote:
Art wrote: "Any thoughts as to why it sgould be so and the scientific facts to support it?" We have plumb lines and bubble levels which allow easy determination of vertical and horizontal directions. We often inhabit a nearly horizontal plane If we are as likely as not to communicate with any particular direction, an omidirectional vertical antenna makes sense. An inclined wire would favor some direction to the detriment of another. Sure a slopimg wire works but doesn`t reach maximum height or length as effectively as a vertical or horizontal wire would. Why a straight dipole and not a V-shaped element? The V-shape corrupts the nulls at the ends of the straight wire. Vertical and horizontal antennas are not solely accidents of history. Best regards, Richard Harrison, KB5WZI Richard, It is well known that near maximum "overall" polarity gain can be obtained by placing a vertical at right angles with respect to earth. Now -a -days maximum gain is required of a certain polarity which requires a specific accuracy of less than 1 degree . So yes, in your working years straight up is good enough but these days of WiFi and all that concentration is applied for purity of polarity which requires a resonance at around 3 degrees to the vertical. This can be determined arithematically according to known laws. Ofcourse as one moves higher this offset angle changes. This same phenomina or tilt angle applies for all polarities where maximum gain is required for purity of polarization.The days have gone where just putting up a wire satisfies all. Regards Art |
Why?
On 5 Apr 2007 10:05:43 -0700, "art" wrote:
On 26 Mar, 21:49, (Richard Harrison) wrote: Art wrote: "Any thoughts as to why it sgould be so and the scientific facts to support it?" We have plumb lines and bubble levels which allow easy determination of vertical and horizontal directions. We often inhabit a nearly horizontal plane If we are as likely as not to communicate with any particular direction, an omidirectional vertical antenna makes sense. An inclined wire would favor some direction to the detriment of another. Sure a slopimg wire works but doesn`t reach maximum height or length as effectively as a vertical or horizontal wire would. Why a straight dipole and not a V-shaped element? The V-shape corrupts the nulls at the ends of the straight wire. Vertical and horizontal antennas are not solely accidents of history. Best regards, Richard Harrison, KB5WZI Richard, It is well known that near maximum "overall" polarity gain can be obtained by placing a vertical at right angles with respect to earth. Now -a -days maximum gain is required of a certain polarity which requires a specific accuracy of less than 1 degree . So yes, in your working years straight up is good enough but these days of WiFi and all that concentration is applied for purity of polarity which requires a resonance at around 3 degrees to the vertical. This can be determined arithematically according to known laws. Ofcourse as one moves higher this offset angle changes. This same phenomina or tilt angle applies for all polarities where maximum gain is required for purity of polarization.The days have gone where just putting up a wire satisfies all. Regards Art Educate me, Art, what is 'polarity' gain? Walt |
Why?
On 5 Apr, 10:32, Walter Maxwell wrote:
On 5 Apr 2007 10:05:43 -0700, "art" wrote: On 26 Mar, 21:49, (Richard Harrison) wrote: Art wrote: "Any thoughts as to why it sgould be so and the scientific facts to support it?" We have plumb lines and bubble levels which allow easy determination of vertical and horizontal directions. We often inhabit a nearly horizontal plane If we are as likely as not to communicate with any particular direction, an omidirectional vertical antenna makes sense. An inclined wire would favor some direction to the detriment of another. Sure a slopimg wire works but doesn`t reach maximum height or length as effectively as a vertical or horizontal wire would. Why a straight dipole and not a V-shaped element? The V-shape corrupts the nulls at the ends of the straight wire. Vertical and horizontal antennas are not solely accidents of history. Best regards, Richard Harrison, KB5WZI Richard, It is well known that near maximum "overall" polarity gain can be obtained by placing a vertical at right angles with respect to earth. Now -a -days maximum gain is required of a certain polarity which requires a specific accuracy of less than 1 degree . So yes, in your working years straight up is good enough but these days of WiFi and all that concentration is applied for purity of polarity which requires a resonance at around 3 degrees to the vertical. This can be determined arithematically according to known laws. Ofcourse as one moves higher this offset angle changes. This same phenomina or tilt angle applies for all polarities where maximum gain is required for purity of polarization.The days have gone where just putting up a wire satisfies all. Regards Art Educate me, Art, what is 'polarity' gain? Walt- Hide quoted text - - Show quoted text - Walter Gain is the total radiation at a particular angle which can be the summation of all polarities such as in the case of vertical and horizontal antennas. If one want's maximum gain with a particular polarization in mind then resonance is to be found at an angle other than 90 degree multiples to the earths surface. This is why I have made the point for years that the yagi has put antennas back nearly 100 years. In amateur work it is not so important tho it does explain why the augument rages between a yagi and a quad with the latter providing a much larger arrival area that allow people to hear more. On top of that the yagi becomes less efficient as one adds elements which means progressive polarity inaccuracy for each added element not only for a particular polarity but also for the increase in reactance for the array as a whole. I have mentioned 3 degrees but that was only by the eye on print out for a single element. I never did associate the tip angle with respect to frequency and height tho I am sure this can be done via Matlab for both a single element or an arrangement of elements. One day they will put this in a book, hopefully the ARRL editions, so the derogatory statements from the older education type guys will cease but I am to old to see that day Regards Art |
Why?
Walter Maxwell wrote:
On 5 Apr 2007 10:05:43 -0700, "art" wrote: On 26 Mar, 21:49, (Richard Harrison) wrote: Art wrote: "Any thoughts as to why it sgould be so and the scientific facts to support it?" We have plumb lines and bubble levels which allow easy determination of vertical and horizontal directions. We often inhabit a nearly horizontal plane If we are as likely as not to communicate with any particular direction, an omidirectional vertical antenna makes sense. An inclined wire would favor some direction to the detriment of another. Sure a slopimg wire works but doesn`t reach maximum height or length as effectively as a vertical or horizontal wire would. Why a straight dipole and not a V-shaped element? The V-shape corrupts the nulls at the ends of the straight wire. Vertical and horizontal antennas are not solely accidents of history. Best regards, Richard Harrison, KB5WZI Richard, It is well known that near maximum "overall" polarity gain can be obtained by placing a vertical at right angles with respect to earth. Now -a -days maximum gain is required of a certain polarity which requires a specific accuracy of less than 1 degree . So yes, in your working years straight up is good enough but these days of WiFi and all that concentration is applied for purity of polarity which requires a resonance at around 3 degrees to the vertical. This can be determined arithematically according to known laws. Ofcourse as one moves higher this offset angle changes. This same phenomina or tilt angle applies for all polarities where maximum gain is required for purity of polarization.The days have gone where just putting up a wire satisfies all. Regards Art Educate me, Art, what is 'polarity' gain? That's when you go to a Polish wedding and put on weight from eating kielbasa. This is related to the "purity of polarization" which is a measure of the quality of the kielbasa served and the Polish music played at the wedding. -- Jim Pennino Remove .spam.sux to reply. |
Why?
Art wrote:
"I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI |
Why?
On 5 Apr, 14:12, (Richard Harrison) wrote:
Art wrote: "I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI No Richard, you are out of date.I'm sure that more about antennas is taught these days that has never showed up in Terman. On the tipping thing many towers have multiple beamms on them and when one is added then owners have to reset their antennas. Now ofcourse one can now move them remotely until max polarity is observed. As far as parallel is concerned, anytime you introduce reactance to the resonance to an individual element you lose out on efficiency if polarity is a concern qand in Termans time polarity was not that much of a concern. I truly believe that most auguments on this newsgroup is because teachings of yesteryear do not match up to present day teachings. With weather forcasters they now direct R.F at a front first with horizontal polarization and then with vertical polarization and then merge the reflected pictures, thus it is imperitivethat polarization is dead on for 3 D analysis of the weather front. Lots of things are done these days that wasn't even thought about as little as 20 years ago such that you must read iee antenna findings every month to keep up. Art |
Why?
On 5 Apr 2007 15:04:13 -0700, "art" wrote:
On 5 Apr, 14:12, (Richard Harrison) wrote: Art wrote: "I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI No Richard, you are out of date.I'm sure that more about antennas is taught these days that has never showed up in Terman. On the tipping thing many towers have multiple beamms on them and when one is added then owners have to reset their antennas. Now ofcourse one can now move them remotely until max polarity is observed. As far as parallel is concerned, anytime you introduce reactance to the resonance to an individual element you lose out on efficiency if polarity is a concern qand in Termans time polarity was not that much of a concern. I truly believe that most auguments on this newsgroup is because teachings of yesteryear do not match up to present day teachings. With weather forcasters they now direct R.F at a front first with horizontal polarization and then with vertical polarization and then merge the reflected pictures, thus it is imperitivethat polarization is dead on for 3 D analysis of the weather front. Lots of things are done these days that wasn't even thought about as little as 20 years ago such that you must read iee antenna findings every month to keep up. Art Art, you still haven't explained what 'polarity' gain is. And what is maximum polarity? I learned polarity as being plus or minus. Are there other 'polarities'? Walt, W2DU |
Why?
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Why?
On Thu, 05 Apr 2007 22:20:51 GMT, Walter Maxwell
wrote: Are there other 'polarities'? Art and AntiArt? Hi Walt, I hope your procedure went well. 73's Richard Clark, KB7QHC |
Why?
On 5 Apr, 15:20, Walter Maxwell wrote:
On 5 Apr 2007 15:04:13 -0700, "art" wrote: On 5 Apr, 14:12, (Richard Harrison) wrote: Art wrote: "I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI No Richard, you are out of date.I'm sure that more about antennas is taught these days that has never showed up in Terman. On the tipping thing many towers have multiple beamms on them and when one is added then owners have to reset their antennas. Now ofcourse one can now move them remotely until max polarity is observed. As far as parallel is concerned, anytime you introduce reactance to the resonance to an individual element you lose out on efficiency if polarity is a concern qand in Termans time polarity was not that much of a concern. I truly believe that most auguments on this newsgroup is because teachings of yesteryear do not match up to present day teachings. With weather forcasters they now direct R.F at a front first with horizontal polarization and then with vertical polarization and then merge the reflected pictures, thus it is imperitivethat polarization is dead on for 3 D analysis of the weather front. Lots of things are done these days that wasn't even thought about as little as 20 years ago such that you must read iee antenna findings every month to keep up. Art Art, you still haven't explained what 'polarity' gain is. And what is maximum polarity? I learned polarity as being plus or minus. Are there other 'polarities'? Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art |
Why?
On Thu, 05 Apr 2007 15:27:05 -0700, Richard Clark wrote:
On Thu, 05 Apr 2007 22:20:51 GMT, Walter Maxwell wrote: Are there other 'polarities'? Art and AntiArt? Hi Walt, I hope your procedure went well. 73's Richard Clark, KB7QHC Sorry Richard, my surgery had to be postponed a second time, first, to wait after my cataract surgery, and second, just before the procedure was to be performed, my dentist discovered an infected tooth. One of its roots was cracked, and I spent one heluva night last night after having the root removed. Consequently, my spinal surgery has been moved to April 18. This is gettin' ridiculous! But thanks for your concern. Walt |
Why?
On 5 Apr 2007 16:13:12 -0700, "art" wrote:
On 5 Apr, 15:20, Walter Maxwell wrote: On 5 Apr 2007 15:04:13 -0700, "art" wrote: On 5 Apr, 14:12, (Richard Harrison) wrote: Art wrote: "I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI No Richard, you are out of date.I'm sure that more about antennas is taught these days that has never showed up in Terman. On the tipping thing many towers have multiple beamms on them and when one is added then owners have to reset their antennas. Now ofcourse one can now move them remotely until max polarity is observed. As far as parallel is concerned, anytime you introduce reactance to the resonance to an individual element you lose out on efficiency if polarity is a concern qand in Termans time polarity was not that much of a concern. I truly believe that most auguments on this newsgroup is because teachings of yesteryear do not match up to present day teachings. With weather forcasters they now direct R.F at a front first with horizontal polarization and then with vertical polarization and then merge the reflected pictures, thus it is imperitivethat polarization is dead on for 3 D analysis of the weather front. Lots of things are done these days that wasn't even thought about as little as 20 years ago such that you must read iee antenna findings every month to keep up. Art Art, you still haven't explained what 'polarity' gain is. And what is maximum polarity? I learned polarity as being plus or minus. Are there other 'polarities'? Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art Art, using correct terminology is essential in preventing misunderstandings, as you have done with 'polarity'. You have confused 'polarity' with 'polarization'--the two are not synonomous, but are distinctly different. Sorry, Art, your misuse of this term has been confusing, rather than enlightening. Are you blaming me for the more than 300 postings on this thread? Walt |
Why?
On 5 Apr, 17:12, Walter Maxwell wrote:
On 5 Apr 2007 16:13:12 -0700, "art" wrote: On 5 Apr, 15:20, Walter Maxwell wrote: On 5 Apr 2007 15:04:13 -0700, "art" wrote: On 5 Apr, 14:12, (Richard Harrison) wrote: Art wrote: "I have mentioned 3 degrees but that was only by eye on print out for a single element." I have set the vertical angle of many highly directional dish feed horns using a bubble level when the path was long. The best setting will be horizontal so that the signal skims the earth when there are no obstructions. Never did subsequent adjustment of elevation angle for best signal ever alter the bubble setting by one iota. Why vertical or horizontal? To get the antennas parallel to each other. That`s why. All electrical charges exert forces on one another. At great distances, the forces become vanishingly small. Even so, every effective antenna is coupled to other conducting matter in its rdiation path to do work in maintaining periodic motion of charges, however faint, throughout the universe. Energy transferred by an antenna to the universe is said to be radiated. Radiation reflected by the ionosphere surrounding the earth is found to be scrambled in its polarization (the direction of its E-field). Energy directly communicated between line-of-sight antennas is most effective when the transmitting and receiving antenna conductors are parallel. Conversely, when they are cross-polarized, loss may exceed 20 dB. Best regards, Richard Harrison, KB5WZI No Richard, you are out of date.I'm sure that more about antennas is taught these days that has never showed up in Terman. On the tipping thing many towers have multiple beamms on them and when one is added then owners have to reset their antennas. Now ofcourse one can now move them remotely until max polarity is observed. As far as parallel is concerned, anytime you introduce reactance to the resonance to an individual element you lose out on efficiency if polarity is a concern qand in Termans time polarity was not that much of a concern. I truly believe that most auguments on this newsgroup is because teachings of yesteryear do not match up to present day teachings. With weather forcasters they now direct R.F at a front first with horizontal polarization and then with vertical polarization and then merge the reflected pictures, thus it is imperitivethat polarization is dead on for 3 D analysis of the weather front. Lots of things are done these days that wasn't even thought about as little as 20 years ago such that you must read iee antenna findings every month to keep up. Art Art, you still haven't explained what 'polarity' gain is. And what is maximum polarity? I learned polarity as being plus or minus. Are there other 'polarities'? Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art Art, using correct terminology is essential in preventing misunderstandings, as you have done with 'polarity'. You have confused 'polarity' with 'polarization'--the two are not synonomous, but are distinctly different. Sorry, Art, your misuse of this term has been confusing, rather than enlightening. Are you blaming me for the more than 300 postings on this thread? Walt- Hide quoted text - - Show quoted text - Walt Now why would I blame you for over 300 postings? Obviously you have created some confusion which is natural for our hobby since we are an old group which gives justification to "there is no fool like an old fool" Nothing personal. Lets face it we oversell experience when in a lot of cases it is the same experience over and over again. Anybody here who remembers the Sputnik probably would not be able to get a degree today or even the same job. On this tilt thing if you look at patents in the 6 million plus area most would not understand what they were referring to, whereas the present day student understands thing fully since he grew up with digital transmissions. Heck most of us retired before the last ten years which is becoming the heydays of antenna research. Yes, as I get older I make the same mistakes as all old people do and you make provision for other old people unless you think your self as perfect as would a younger person who just got his degree and was up to date. The difference ofcourse is the young student wants to prove things to himself until he gets behind technically when he then asks for proof from others. If I look back at the past arguments on my threads many pull out the 50 year old books that we have stored away. The modern student will look up Google and even if he is a few years out of school would have checked the computor for reference to "adjusting antennas" or "tilting antennas"to get up to date where as the old timer thinks he is still back in the old days so his knoweledge is up to date and cannot adapt to the present situation he there is no reference to that in my books.Odd thing I saw the other day was a book by Terman and would you believe it nowhere in the book does the words of "maxwell" or Gauss" show up so they must be imaginary also. Yup, Walt as you get older you will find that a lot more people are mixed up except you and need to be told so until the time come that more people are saying it to you forcing you to be more tolerant. Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas e.t.c instead of discarding information in favour of the opportunity to mock while the younger more knowledgable members give a quiet smile to themselves. Walt were you aware of the reasons for tipping? I doubt it because you probably can remember the Sputnik when the standards of education was lower and Google was not around. Never heard you come forward with respect to the Gaussian and Maxwell argument either before or after the young M.I.T guy put every body straight or did you know it anyway but just didn't want to correct people then? Art |
Why?
On 5 Apr 2007 18:04:15 -0700, "art" wrote:
On 5 Apr, 17:12, Walter Maxwell wrote: On 5 Apr 2007 16:13:12 -0700, "art" wrote: snip Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art Art, using correct terminology is essential in preventing misunderstandings, as you have done with 'polarity'. You have confused 'polarity' with 'polarization'--the two are not synonomous, but are distinctly different. Sorry, Art, your misuse of this term has been confusing, rather than enlightening. Are you blaming me for the more than 300 postings on this thread? Walt- Hide quoted text - - Show quoted text - Walt Now why would I blame you for over 300 postings? Obviously you have created some confusion which is natural for our hobby since we are an old group which gives justification to "there is no fool like an old fool" Nothing personal. Lets face it we oversell experience when in a lot of cases it is the same experience over and over again. Anybody here who remembers the Sputnik probably would not be able to get a degree today or even the same job. On this tilt thing if you look at patents in the 6 million plus area most would not understand what they were referring to, whereas the present day student understands thing fully since he grew up with digital transmissions. Heck most of us retired before the last ten years which is becoming the heydays of antenna research. Yes, as I get older I make the same mistakes as all old people do and you make provision for other old people unless you think your self as perfect as would a younger person who just got his degree and was up to date. The difference ofcourse is the young student wants to prove things to himself until he gets behind technically when he then asks for proof from others. If I look back at the past arguments on my threads many pull out the 50 year old books that we have stored away. The modern student will look up Google and even if he is a few years out of school would have checked the computor for reference to "adjusting antennas" or "tilting antennas"to get up to date where as the old timer thinks he is still back in the old days so his knoweledge is up to date and cannot adapt to the present situation he there is no reference to that in my books.Odd thing I saw the other day was a book by Terman and would you believe it nowhere in the book does the words of "maxwell" or Gauss" show up so they must be imaginary also. Yup, Walt as you get older you will find that a lot more people are mixed up except you and need to be told so until the time come that more people are saying it to you forcing you to be more tolerant. Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas e.t.c instead of discarding information in favour of the opportunity to mock while the younger more knowledgable members give a quiet smile to themselves. Walt were you aware of the reasons for tipping? I doubt it because you probably can remember the Sputnik when the standards of education was lower and Google was not around. Never heard you come forward with respect to the Gaussian and Maxwell argument either before or after the young M.I.T guy put every body straight or did you know it anyway but just didn't want to correct people then? Art Art, you say I have created confusion? Over what? Confusion? How about responding to your misuse of the term 'polarity'? Now that's confusion. And you say that some MIT guy put everybody straight? Just what is it the everybody needed straightening about that the MIT guy is supposed to have done? And are you implying that Terman, Kraus, Johnson, et al are wrong, and that we need 'straightening out' because we learned it wrong from these masters of 50 years ago? And you're also saying that our educational standards are better now? Art, what have you been smoking? And are you also saying that the new graduate with no hands-on experience outweighs a graduate of 30 years ago with experience gained during those 30 years? What planet are you from, Art, certainly not Earth. Think about it, Walt, W2DU |
Why?
On 5 Apr, 19:54, Walter Maxwell wrote:
On 5 Apr 2007 18:04:15 -0700, "art" wrote: On 5 Apr, 17:12, Walter Maxwell wrote: On 5 Apr 2007 16:13:12 -0700, "art" wrote: snip Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art Art, using correct terminology is essential in preventing misunderstandings, as you have done with 'polarity'. You have confused 'polarity' with 'polarization'--the two are not synonomous, but are distinctly different. Sorry, Art, your misuse of this term has been confusing, rather than enlightening. Are you blaming me for the more than 300 postings on this thread? Walt- Hide quoted text - - Show quoted text - Walt Now why would I blame you for over 300 postings? Obviously you have created some confusion which is natural for our hobby since we are an old group which gives justification to "there is no fool like an old fool" Nothing personal. Lets face it we oversell experience when in a lot of cases it is the same experience over and over again. Anybody here who remembers the Sputnik probably would not be able to get a degree today or even the same job. On this tilt thing if you look at patents in the 6 million plus area most would not understand what they were referring to, whereas the present day student understands thing fully since he grew up with digital transmissions. Heck most of us retired before the last ten years which is becoming the heydays of antenna research. Yes, as I get older I make the same mistakes as all old people do and you make provision for other old people unless you think your self as perfect as would a younger person who just got his degree and was up to date. The difference ofcourse is the young student wants to prove things to himself until he gets behind technically when he then asks for proof from others. If I look back at the past arguments on my threads many pull out the 50 year old books that we have stored away. The modern student will look up Google and even if he is a few years out of school would have checked the computor for reference to "adjusting antennas" or "tilting antennas"to get up to date where as the old timer thinks he is still back in the old days so his knoweledge is up to date and cannot adapt to the present situation he there is no reference to that in my books.Odd thing I saw the other day was a book by Terman and would you believe it nowhere in the book does the words of "maxwell" or Gauss" show up so they must be imaginary also. Yup, Walt as you get older you will find that a lot more people are mixed up except you and need to be told so until the time come that more people are saying it to you forcing you to be more tolerant. Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas e.t.c instead of discarding information in favour of the opportunity to mock while the younger more knowledgable members give a quiet smile to themselves. Walt were you aware of the reasons for tipping? I doubt it because you probably can remember the Sputnik when the standards of education was lower and Google was not around. Never heard you come forward with respect to the Gaussian and Maxwell argument either before or after the young M.I.T guy put every body straight or did you know it anyway but just didn't want to correct people then? Art Art, you say I have created confusion? Over what? Confusion? How about responding to your misuse of the term 'polarity'? Now that's confusion. And you say that some MIT guy put everybody straight? Just what is it the everybody needed straightening about that the MIT guy is supposed to have done? And are you implying that Terman, Kraus, Johnson, et al are wrong, and that we need 'straightening out' because we learned it wrong from these masters of 50 years ago? And you're also saying that our educational standards are better now? Art, what have you been smoking? And are you also saying that the new graduate with no hands-on experience outweighs a graduate of 30 years ago with experience gained during those 30 years? What planet are you from, Art, certainly not Earth. Think about it, Walt, W2DU- Hide quoted text - - Show quoted text - |
Why?
On 5 Apr, 19:54, Walter Maxwell wrote:
On 5 Apr 2007 18:04:15 -0700, "art" wrote: On 5 Apr, 17:12, Walter Maxwell wrote: On 5 Apr 2007 16:13:12 -0700, "art" wrote: snip Walt, W2DU- Hide quoted text - - Show quoted text - Walt, if you are looking for maximum horizontal or any other polarity it can only be obtained by removal of reception of other polarities, this maximum is obtained by having the radiator at 90 degree multiples with respect to earth. You can prove this to your self anytime by calculating max horizontal gain by progressively tipping a dipole while keeping it resonant until the maximum is reached. If your concern is for total gain without regard to polarity mix then the vertical position total gain will equal the total gain of the tipped dipole. The difference is that one arrangement has a mixture of polarities where-as the tipped antenna will only provide a single polarity. If another element or anything else is added near enough to add reactance then the prior antenna must be adjusted to remove it, thus the reason for remote adjustment which is much cheaper to maintain rather than regular trips up a tower by maintanance men. Hopefully Walter this will bring you up to date. I have no reason for a 300 posting thread as I do not intend to write rev 3 of Reflections or anything else. Regards Art Art, using correct terminology is essential in preventing misunderstandings, as you have done with 'polarity'. You have confused 'polarity' with 'polarization'--the two are not synonomous, but are distinctly different. Sorry, Art, your misuse of this term has been confusing, rather than enlightening. Are you blaming me for the more than 300 postings on this thread? Walt- Hide quoted text - - Show quoted text - Walt Now why would I blame you for over 300 postings? Obviously you have created some confusion which is natural for our hobby since we are an old group which gives justification to "there is no fool like an old fool" Nothing personal. Lets face it we oversell experience when in a lot of cases it is the same experience over and over again. Anybody here who remembers the Sputnik probably would not be able to get a degree today or even the same job. On this tilt thing if you look at patents in the 6 million plus area most would not understand what they were referring to, whereas the present day student understands thing fully since he grew up with digital transmissions. Heck most of us retired before the last ten years which is becoming the heydays of antenna research. Yes, as I get older I make the same mistakes as all old people do and you make provision for other old people unless you think your self as perfect as would a younger person who just got his degree and was up to date. The difference ofcourse is the young student wants to prove things to himself until he gets behind technically when he then asks for proof from others. If I look back at the past arguments on my threads many pull out the 50 year old books that we have stored away. The modern student will look up Google and even if he is a few years out of school would have checked the computor for reference to "adjusting antennas" or "tilting antennas"to get up to date where as the old timer thinks he is still back in the old days so his knoweledge is up to date and cannot adapt to the present situation he there is no reference to that in my books.Odd thing I saw the other day was a book by Terman and would you believe it nowhere in the book does the words of "maxwell" or Gauss" show up so they must be imaginary also. Yup, Walt as you get older you will find that a lot more people are mixed up except you and need to be told so until the time come that more people are saying it to you forcing you to be more tolerant. Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas e.t.c instead of discarding information in favour of the opportunity to mock while the younger more knowledgable members give a quiet smile to themselves. Walt were you aware of the reasons for tipping? I doubt it because you probably can remember the Sputnik when the standards of education was lower and Google was not around. Never heard you come forward with respect to the Gaussian and Maxwell argument either before or after the young M.I.T guy put every body straight or did you know it anyway but just didn't want to correct people then? Art Art, you say I have created confusion? Over what? Walter, you complained about not getting as many responses as I, I accept that sometimes my threads are as long as 50 posts instead of just a few for agreement Yours is now 300 is it you or others who are confused.You think about it Confusion? How about responding to your misuse of the term 'polarity'? Now that's confusion. And you say that some MIT guy put everybody straight? Just what is it the everybody needed straightening about that the MIT guy is supposed to have done? Well one person finally concurred and nobody refuted this concurrence so you think the majority are correct because they didn't agree? And are you implying that Terman, Kraus, Johnson, et al are wrong, and that we need 'straightening out' because we learned it wrong from these masters of 50 years ago? You remembered it from 50 years ago, that is a lot of difference from truly understanding it. The MIT and another individual from down under agreed with the mathematics that underlined what I was talking about invoking what the masters stated. So it is you who must have learned it wrong 50 years ago but you have time to correct the M.I.T guy and the guy from down under that they had misused mathematics some how and came up with formular that disputes the masters. Actually the guy from MIT gave a terrific response that didnot receive any reject from anybody including you. And you're also saying that our educational standards are better now? Art, what have you been smoking? And are you also saying that the new graduate with no hands-on experience outweighs a graduate of 30 years ago with experience gained during those 30 years? Yes I do unless the experienced guy kept up with progress such as a Professor. When I spoke about polarity and tipping a younger person knowing what I was talking about would have adapted while you who knew nothing about the subject could not adapt. If you are not aware of modern day practices then you would not get hired today. New graduates always get the nod over senior citizens. What planet are you from, Art, certainly not Earth. It is on earth we are talking about when we talk of tilting and the correlattion of gaussian theory with respect to radiation. You have presented nothing with respect to supposed inaccuracy which says you are ignorant of it. Why else does one ridicule another person by moving away from science ? So if you disagree with the tipping process for antennas or if you disagree with the response from M.I.T. then put your stake in the ground and state your superiority in mathematacs rather than driving the stake into the messenger. If you take this small step I assure you this thread will not last as long as yours. You may be able to distort science but you can't refute mathematics by killing the mathematician. Perhaps it is better that you put your eyes and ears back into the ground . On the other hand I would be impressed if you could prove your position but you have shown that you can't by burying your head in the sand. Walter we are all getting older and it is harder to keep up with things, that is something that we all have to accept and you are not immune to it, and it shows Art Think about it, Walt, W2DU- Hide quoted text - - Show quoted text - |
Why?
On 26 Mar, 19:27, "Jimmie D" wrote:
"art" wrote in message ups.com... Antennas seemed to have evolved into structures that are parallel or at right angles to the earths surface Why is this or is it asthetics that is driving this thinking? My research on the subject evolves around the vector formation of radiation and where the addition of the vectors involved which creats radiation is at an angle to the radiator.. This suggests that for best radiative advantage it is this vector that should be parallel to the earths surface and not the physical radiator. This appears to be born out by following my Gaussian approach to radiator design. So the question of habitual arrangement of antenna arrays parallel or at right angles to the earths surface as being the best arrangement needs some sort of validation. Any thoughts as to why it should be so and the scientific facts that support it? Art What angle did you derive was the best angle to mount an anenna? Please show experimental data to backup your conclusions. Jimmie- Hide quoted text - - Show quoted text - Heh Jimmie, I was looking at a book that showed the scanning lines of a tv. It also showed aperture as being bisected equally by these same scanning lines. Since aperture is directly related to gain one could probably state that the angle of the scan lines on a TV is directly related to the tipping angle for radiation. Both are magnetically related ie angle of release of an electron so you may get a better answer from a T.V. technician with respect to angles than ham radio operators. Isn't science great when your brain is nimble and curious! Art |
Why?
Art wrote:
"Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI |
Why?
On 6 Apr, 08:48, (Richard Harrison) wrote:
Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI I will have to read it for myself, it doesn't seem to be relavent but I'll check to see if you are seeing things in context. The book I quoted regarding scan lines was Terman by the way. The Kraus book did not present any great changes to older versions which is often the case when publishers present 2nd or 3rd editions to squeeze any remaining profits However I will read it to see if the microwave portion is up to date rather than a reissue |
Why?
Some of the best reasons are empirical. Numerous studies have shown
that the clutter return from the sea surface is considerably higher in horizontal polarization. I am on vacation, so I don't have my Skolnik handy to say exactly how much. Anyway, this favors a vertical polarization. Similarly, practical considerations make vertical polarization the best for mobile applications. The 1/4 whip is the simplest antenna structure on a mobile platform. While base stations could as easily use horizontal or vertical, any mobile horizontal antenna will require extra structure to implement. In both of these applications there is nothing be gained by going to any other polarization than vertical for these uses. In cases where horizontal polarization has an advantage, there is no reason to go partly vertical. So that is why the world end up either being vertical or horizontal for the most part. Where it doesn't, polarization usually doesn't matter or is less of a concern than other reasons (see inverted vees and sloping dipoles). Erich KA6AMD Jimmie D wrote: "art" wrote in message oups.com... On 27 Mar, 15:12, (Richard Harrison) wrote: Art wrote: "I have his (Kraus`) second edition (Antennas) and I find no mention of radiation from the beginning where current is applied onward." I think I have that edition too. If you review the chapter on "Point Sources" you`ll find: power patterns, a power theorem and its application to isotropic sources, rediation intensity, source with hemispheric power pattern, unidirectional cosine power pattern, etc., etc.. The new, now available 3rd ed. of "Antennas" by Kraus, Marhefka, and a host of others is greatly expanded and improved. It is worth the investment. Being uncertain of what Art really wants, doesn`t stop me from advising him to start by having a look at the famous Sommerfeld formula on page 804 of Terman`s 1955 opus. It predicts 1 kilowatt will produce 186 mv per m at a distance of 1 mile from a short vertical transmitting antenna given a certain ground conductivity and other conditions. Best regards, Richard Harrison, KB5WZI Richard, I have lots of books but as yet have not found the answer even tho many have posted none appear to really have an answer other than to throw stones. You apparently have found the answer! Could you quote from the books that you are refering to the angle of radiation relative to the radiator, thats it ? If you can't understand that then relay to me the angle of a radiation front relative to a radiator, I'm sure some other people are interested in what you found. Even better, let me know the TOA of a dipole in free space and how much it varies to that of the same dipole over a perfect ground. Use a computor program if you like, anything that sheds light on the matter . The books say that a horizontal "v" antenna should be tipped for max gain, doesn't that raise your interest about the reasoning and mathematics behind this? Jimmie D asked me to state this angle but I have only a expensive computor program that doesn't give the math with the answer. Please read off the angle and the specifics so we all can move on, I don't want a 160 thread postings some thrust upon Walt Art The V antenna is a terminated traveling wave antenna the dipoles that you have been refering to are standingwave antennas. You are comparing apples and oranges. The best I can tell is that all other references you made to tilt have been perpedicular to the direction of the wave front. The V antenna is tilted in the direction of the wave front, more apples and oranges. Throw in some grapes and pineapple and we will have fruit salad. Jimmie |
Why?
"art" wrote in message oups.com... On 26 Mar, 19:27, "Jimmie D" wrote: "art" wrote in message ups.com... Antennas seemed to have evolved into structures that are parallel or at right angles to the earths surface Why is this or is it asthetics that is driving this thinking? My research on the subject evolves around the vector formation of radiation and where the addition of the vectors involved which creats radiation is at an angle to the radiator.. This suggests that for best radiative advantage it is this vector that should be parallel to the earths surface and not the physical radiator. This appears to be born out by following my Gaussian approach to radiator design. So the question of habitual arrangement of antenna arrays parallel or at right angles to the earths surface as being the best arrangement needs some sort of validation. Any thoughts as to why it should be so and the scientific facts that support it? Art What angle did you derive was the best angle to mount an anenna? Please show experimental data to backup your conclusions. Jimmie- Hide quoted text - - Show quoted text - Heh Jimmie, I was looking at a book that showed the scanning lines of a tv. It also showed aperture as being bisected equally by these same scanning lines. Since aperture is directly related to gain one could probably state that the angle of the scan lines on a TV is directly related to the tipping angle for radiation. Both are magnetically related ie angle of release of an electron so you may get a better answer from a T.V. technician with respect to angles than ham radio operators. Isn't science great when your brain is nimble and curious! Art It must be wonderful to wake up ina new world every morning. Jimme |
Why?
Phil wrote:
Some of the best reasons are empirical. Numerous studies have shown that the clutter return from the sea surface is considerably higher in horizontal polarization. I am on vacation, so I don't have my Skolnik handy to say exactly how much. Anyway, this favors a vertical polarization. Similarly, practical considerations make vertical polarization the best for mobile applications. The 1/4 whip is the simplest antenna structure on a mobile platform. While base stations could as easily use horizontal or vertical, any mobile horizontal antenna will require extra structure to implement. In both of these applications there is nothing be gained by going to any other polarization than vertical for these uses. In cases where horizontal polarization has an advantage, there is no reason to go partly vertical. So that is why the world end up either being vertical or horizontal for the most part. Where it doesn't, polarization usually doesn't matter or is less of a concern than other reasons (see inverted vees and sloping dipoles). Erich KA6AMD Interesting that you think that vertical is the best polarization for mobile operation. I have done a lot of testing on 2 meters with equal gain end to end that would indicate that you are quite mistaken. Horizontal polarization from a fixed station to a mobile, or a mobile station to a mobile is much more effective if horizontally polarized. The reasons for this are well documented, so I won't go into that. The most obvious notable difference is that "picket fence" fading is much worse when vertically polarized. The major reason vertical polarization is used (for FM) is that it is easy. SSB/CW on VHF/UHF is still horizontal when mobile. tom K0TAR |
Why?
On 6 Apr, 08:48, (Richard Harrison) wrote:
Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art |
Why?
"art" wrote in message oups.com... On 6 Apr, 08:48, (Richard Harrison) wrote: Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art Perhaps you should actually make an effort to explain why you see the relationships you see. I can think of no reason why anyone should be expected to go into great detail to explain your fallacies while you use almost no effort to explain why you think you are right. Jimmie |
Why?
On 8 Apr, 17:52, "Jimmie D" wrote:
"art" wrote in message oups.com... On 6 Apr, 08:48, (Richard Harrison) wrote: Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art Perhaps you should actually make an effort to explain why you see the relationships you see. I can think of no reason why anyone should be expected to go into great detail to explain your fallacies while you use almost no effort to explain why you think you are right. Jimmie- Hide quoted text - - Show quoted text - Jimmie As I said earlier the crt picture was in a Terman book. The picture showed a series of scan lines across the screen at a slight angle. Drawn at right angles to the sloping lines was a square i.e. bisected by the scan line. It was stated that the square represented aperture. Thus both the scan line and the aperture was tilted away from 90 degrees to the earth. As I said earlier for purity of polarization a vertical dipole would have to be tilted approx 3 degrees. All this is a repeat of my last post which I consider an effort to rebutt what you call a "fallacy". I see similarities with what I stated earlier with respect to antennas. I never said I was correct to compare these analogies, I just put them forward for thought knowing that when the sets are assembled they are positioned to the north with the crt in a fixed position and the yoke is then manipulated to its best angle tho it has been known for T.V. pictures to be skewed by 3 degrees or so. Yup, I did make some effort don't you think? Art |
Why?
On 8 Apr, 17:52, "Jimmie D" wrote:
"art" wrote in message oups.com... On 6 Apr, 08:48, (Richard Harrison) wrote: Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art Perhaps you should actually make an effort to explain why you see the relationships you see. I can think of no reason why anyone should be expected to go into great detail to explain your fallacies while you use almost no effort to explain why you think you are right. such that the horizontal vecot Jimmie- Hide quoted text - - Show quoted text - I think I will try one more time with respect to tilt angle. ARRL publications suggest that a vertical dipole only radiates a vertically polarized radiation Amatures read these publication and follow suit on their thinking, if they can think that is,anything else must be wrong. Well Jimmie you must surely know that only one electron stream travels at the same angle as the dipole, any thing else does not. Therefore the resultant vector angle cannot be parallel to the radiating member and thus will radiate some horizontal radiation. To remove vertical radiation you must tip the vertical dipole until the horizontal vector is removed. All very simple. Still to difficult for you? Well try this. Use your antenna program to determine the horizontal radiation and vertical radiation of a vertical dipole. Now model a tipped dipole until the horizontal radiation is removed leaving only vertical radiation and "Bingo" you should now understand and possibly other amateurs will now question what they read in books. Tho I doubt that since learners seem to only to be able to regurgitate rather than activate their brain. If you are still not comfortable read Maxwells laws and activate your own brain and follow the leads given. There is no way I can activate your brain or any of the pseudo experts brains on line. Art Art |
Why?
"art" wrote in message ups.com... On 8 Apr, 17:52, "Jimmie D" wrote: "art" wrote in message oups.com... On 6 Apr, 08:48, (Richard Harrison) wrote: Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art Perhaps you should actually make an effort to explain why you see the relationships you see. I can think of no reason why anyone should be expected to go into great detail to explain your fallacies while you use almost no effort to explain why you think you are right. Jimmie- Hide quoted text - - Show quoted text - Jimmie As I said earlier the crt picture was in a Terman book. The picture showed a series of scan lines across the screen at a slight angle. Drawn at right angles to the sloping lines was a square i.e. bisected by the scan line. It was stated that the square represented aperture. Thus both the scan line and the aperture was tilted away from 90 degrees to the earth. As I said earlier for purity of polarization a vertical dipole would have to be tilted approx 3 degrees. All this is a repeat of my last post which I consider an effort to rebutt what you call a "fallacy". I see similarities with what I stated earlier with respect to antennas. I never said I was correct to compare these analogies, I just put them forward for thought knowing that when the sets are assembled they are positioned to the north with the crt in a fixed position and the yoke is then manipulated to its best angle tho it has been known for T.V. pictures to be skewed by 3 degrees or so. Yup, I did make some effort don't you think? Art Not much, just leaps from one thought to another without explanaion. Jimmie |
Why?
"art" wrote in message oups.com... On 8 Apr, 17:52, "Jimmie D" wrote: "art" wrote in message oups.com... On 6 Apr, 08:48, (Richard Harrison) wrote: Art wrote: "Frankly a lot of people on this net need to get up to speed with respect to radiation such as tipped antennas ---." Yesterday`s response seems to have been gobbled in cyber space. Not all my reference books are over 50 years old. One of my best was published in 2003 although its principal author was born in 1910. He is J.D. Kraus, but he had numerous and likely younger collaborators, 6 of whom are listed as co-authors. The title: "Antennas For All Applications. 3rd edition". On page 297 is found an item which illustrates what happens when you tip an antenna. It is titled: "Antenna Rotation Experiments": "Consider the radio circuit shown in Fig. 8-74a in which one antenna is circularly polarized (a turnstile?) and the other is linearly polarized. If one of the antennas is rotated about its axis a frequency f (r/s), the received signal is shifted to F + or - f, where F is the transmitter frequency." Fig. 8-74 notes: "Antenna rotation produces amplitude modulation." Of course it does. When the linear antenna is aligned parallel to one axis of the CP antenna, the signal is maximum. When the linear antenna is most misaligned with either axis of the CP antenna, signal is a minimum. The example demonstrates why polarization alignment, not tipping or tilt, is usually important. Best regards, Richard Harrison, KB5WZI Richard, I couldn't find my Kraus book so I will have to let your comment go. I did look in the Jasik book on parasitic elements. It said"A parrasitic element properly tuned will operate in phase-and- field relationships approximating those computed.In multi element arrays, independent control and phase and amplitude is required and parasitics should be avoided. However, they may be employed in antennas designed primarily for power gain" To me this describes a yagi with parasitic elements designed for power gain regardless of the mix of polarisation. The Gauss system which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE. A yagi in a 90 degree multiple of earth does operate in a field relationship because of its multi phase radiation where as the gaussion tilts to remove unwanted phase and keeps only the required phase. This is extremely important in cell transmittions since channels are only of use when the polarisation is correct and any area that does not comprise of the correct polarisation results in a dropped call. In my last post I mentioned the slope between scanning lines on a T.V. as a reference line for true polarity. Any comment with respect to the veracity of that statement since I see a direct corrorally between that and radiation tilt angles? Best regards Art Perhaps you should actually make an effort to explain why you see the relationships you see. I can think of no reason why anyone should be expected to go into great detail to explain your fallacies while you use almost no effort to explain why you think you are right. such that the horizontal vecot Jimmie- Hide quoted text - - Show quoted text - I think I will try one more time with respect to tilt angle. ARRL publications suggest that a vertical dipole only radiates a vertically polarized radiation Amatures read these publication and follow suit on their thinking, if they can think that is,anything else must be wrong. Well Jimmie you must surely know that only one electron stream travels at the same angle as the dipole, any thing else does not. Therefore the resultant vector angle cannot be parallel to the radiating member and thus will radiate some horizontal radiation. To remove vertical radiation you must tip the vertical dipole until the horizontal vector is removed. All very simple. Still to difficult for you? Well try this. Use your antenna program to determine the horizontal radiation and vertical radiation of a vertical dipole. Now model a tipped dipole until the horizontal radiation is removed leaving only vertical radiation and "Bingo" you should now understand and possibly other amateurs will now question what they read in books. Tho I doubt that since learners seem to only to be able to regurgitate rather than activate their brain. If you are still not comfortable read Maxwells laws and activate your own brain and follow the leads given. There is no way I can activate your brain or any of the pseudo experts brains on line. I have read Maxwells laws and are familar with them, I have been since high school and nothing in them indcates what you say is feasable. My antenna program indicates that all of the signal in a vertically mounted antenna is vertically polarized. I have racked my mind to see how you could come up with another conclusion and must assume you are confusing take off angle with polarization. How do you get the idea that only one electron stream flows vertcally, obviously your understanding of how electrons flow in a conductor is flawed. The part of their movement that is responsible for current flow is more of a vibration than a flow, definately not forming streams. Since your theory is based on these misaligned streams which dont exist then your theory does not exist either. If we assume your understanding of electron flow is correct then there will be a very huge number of of streams traving at various angles the length of the antenna. If the radiator is sufficentlyly small in cross sectional area this angle will be limited to a being very small angle, we will asume your three degees, much smaller is more realistic. Now to maitain an omni pattern wich direction due you propose to tilt it. If yor theory has any validity at all at best you will correct it in just one direction fora relatively small number of streams and make it worse in all others. Again assuming there is some validity to what you say the polarization of an antenna mounted vertically to the earth at point a will have exactly the same polarity as one mounted somewhere else at point B reguardless of what you believe is the final polarity of these antennas they will be identical and this identicalness of polarity is the best arrangement for two antennas transmitting and receiving one anothers signal. Jimmie Art Art |
Why?
Art wrote:
"The Gauss system, which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE." Parasitic arrays can also use independent control of phase and amplitude, I worked with curtain antenna arrays in the 1950`s used for shortwave broadcasting. The array consisted of (4) 1/2-wave dipoles, 2 over 2 all in the same plane, separated vertically by a 1/2 wavelength and suspended over the earth by a gap of 1/2-wavelength. An identical dipole array was suspended immediately behind the driven dipoles. It served as a parasitic reflector. The harness connected to the parasitic array was identical to that connected to the driven elements except that instead of being connected to the transmitter, it was connected to tuning stubs. We used an RCA WM 30A broadcast phase monitor with sampling loops suspended on driven and parasitic elements to adjust phasing of the reflector. Best regards, Richard Harrison, KB5WZI |
Why?
Art wrote:
"The picture showed a seies of scan lnes across the screen at a slight angle." Yes. I think that is right but I learned about TV back in 1948 and haven`t thought about it much since. As I recall, the designers of the U.S. TV system decided to construct a picture consisting of two interlaced fields. The first starts at the center of the screen at the very top of the picture, sweeping to the right on a slight downward slope, then retracing quickly to the lefthand edge of the picture. There the next parallel but slightly lower line of field or frame starts being written. As I see it, the tilt or slope is strictly an arbitrary decision of the designer but conformity is required of the standard to work within the original system. Best regards, Richard Harrison, KB5WZI |
Why?
On 9 Apr, 08:12, (Richard Harrison) wrote:
Art wrote: "The Gauss system, which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE." Parasitic arrays can also use independent control of phase and amplitude, I worked with curtain antenna arrays in the 1950`s used for shortwave broadcasting. The array consisted of (4) 1/2-wave dipoles, 2 over 2 all in the same plane, separated vertically by a 1/2 wavelength and suspended over the earth by a gap of 1/2-wavelength. An identical dipole array was suspended immediately behind the driven dipoles. It served as a parasitic reflector. The harness connected to the parasitic array was identical to that connected to the driven elements except that instead of being connected to the transmitter, it was connected to tuning stubs. We used an RCA WM 30A broadcast phase monitor with sampling loops suspended on driven and parasitic elements to adjust phasing of the reflector. Best regards, Richard Harrison, KB5WZI There is no problem with that for shortwave broadcasts since not only are you looking for a broard arrival area you are also looking at a skip distance wheret different polarization arrives at the same polarity. If it were a Gauss form it would be of a higher power but a much smaller arrival area which means a smaller audience. Though I must add that a Gaussian arrival area can be tailor made rather than the narrow lobe associated with other radiators. It is when " boresight" is of a concern that such arrays fall in disfavor, as in cell phone work and satellite work where one should take note of maximum polarization purity. Tho' why satelites still use turnstiles is beyond me since only one polarization is required but I am sure there must be a reason, possibly because there is not an overpowering need of multi monitoring communication channels. Regards Art |
Why?
Richard Harrison wrote:
Art wrote: "The picture showed a seies of scan lnes across the screen at a slight angle." Yes. I think that is right but I learned about TV back in 1948 and haven`t thought about it much since. As I recall, the designers of the U.S. TV system decided to construct a picture consisting of two interlaced fields. The first starts at the center of the screen at the very top of the picture, sweeping to the right on a slight downward slope, then retracing quickly to the lefthand edge of the picture. There the next parallel but slightly lower line of field or frame starts being written. As I see it, the tilt or slope is strictly an arbitrary decision of the designer but conformity is required of the standard to work within the original system. The tilt of the horizontal scan lines is simply a consequence of the linear vertical deflection ramp being applied to the yoke at the same time as the horizontal deflection. Roy Lewallen, W7EL |
Why?
On 9 Apr, 10:13, Roy Lewallen wrote:
Richard Harrison wrote: Art wrote: "The picture showed a seies of scan lnes across the screen at a slight angle." Yes. I think that is right but I learned about TV back in 1948 and haven`t thought about it much since. As I recall, the designers of the U.S. TV system decided to construct a picture consisting of two interlaced fields. The first starts at the center of the screen at the very top of the picture, sweeping to the right on a slight downward slope, then retracing quickly to the lefthand edge of the picture. There the next parallel but slightly lower line of field or frame starts being written. As I see it, the tilt or slope is strictly an arbitrary decision of the designer but conformity is required of the standard to work within the original system. The tilt of the horizontal scan lines is simply a consequence of the linear vertical deflection ramp being applied to the yoke at the same time as the horizontal deflection. Roy Lewallen, W7EL- Hide quoted text - - Show quoted text - I saw that as analagous to a horizontal beam i.e current with magnetic electrons at right angles in a time varying field, the resultant vector being at an angle with respect to the horizontal sweepof the deflection signal. Either way, since all vectors do not move in the same direction the resultant vector cannot align with any existing vector.In this case it presents an oportunity for the designer to have maximum brilliance together with ramp. Who says you can't have your cake and eat it to! Art |
Why?
On Apr 9, 12:19 pm, "art" wrote:
On 9 Apr, 08:12, (Richard Harrison) wrote: Art wrote: "The Gauss system, which does not use parasitics and therefore pursues the independent control AND PHASE AND AMPLITUDE." Parasitic arrays can also use independent control of phase and amplitude, I worked with curtain antenna arrays in the 1950`s used for shortwave broadcasting. The array consisted of (4) 1/2-wave dipoles, 2 over 2 all in the same plane, separated vertically by a 1/2 wavelength and suspended over the earth by a gap of 1/2-wavelength. An identical dipole array was suspended immediately behind the driven dipoles. It served as a parasitic reflector. The harness connected to the parasitic array was identical to that connected to the driven elements except that instead of being connected to the transmitter, it was connected to tuning stubs. We used an RCA WM 30A broadcast phase monitor with sampling loops suspended on driven and parasitic elements to adjust phasing of the reflector. Best regards, Richard Harrison, KB5WZI There is no problem with that for shortwave broadcasts since not only are you looking for a broard arrival area you are also looking at a skip distance wheret different polarization arrives at the same polarity. If it were a Gauss form it would be of a higher power but a much smaller arrival area which means a smaller audience. Though I must add that a Gaussian arrival area can be tailor made rather than the narrow lobe associated with other radiators. It is when " boresight" is of a concern that such arrays fall in disfavor, as in cell phone work and satellite work where one should take note of maximum polarization purity. Tho' why satelites still use turnstiles is beyond me since only one polarization is required but I am sure there must be a reason, possibly because there is not an overpowering need of multi monitoring communication channels. Regards Art If this fact is beyound you as you say then you have no business lecturing other people on antenna theory and that you are as brainless as you claim others to be. They are circularly polarized because satellites tumble in space resulting in there polarity constantly changing, also other reason why the polarity of an earth station would not match that of a satellite, look them up. This can be a real problem with a linear polarity antenna but no problem at all for a circular polarity antenna such as the turnstile. Jimmie |
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